Vehicle frames may include a variety of beams that make up structure of the vehicle. Cross beams may extend between longitudinal frame rails to provide sufficient resistance to side impacts. Pillars are beams that support the vehicle roof and resist crush loads. Bumper support beams extend between a vehicle frame and front or rear bumpers to absorb energy associated with front or rear impacts.
More stringent fuel and emissions standards have created the need to reduce the weight of vehicles. However, vehicle safety standards and ratings require strengthening of beams to increase absorption of energy and improve crash performance. Stronger lighter-weight materials have been incorporated in vehicles by primarily changing the materials of the beams. But changing to lightweight materials may not be sufficient to minimize weight and improve crash worthiness.
Under axial loading conditions, axial collapse of a strengthening member may proceed in a buckling mode that is initiated in a middle of the strengthening member before moving to a top of the strengthening member in a non-progressive manner. This may increase the variation in crash behaviors among replicate samples, and result in less impact energy being absorbed compared to a progressive collapse mode.
The present disclosure is directed to achieving fuel economy driven weight reduction in vehicle beams and structural walls while maximizing compressive strength and energy absorption during a crash. This disclosure is also directed to providing a consistent set of beams having various strengths and fewer variations of the outer dimensions.